Identifying Latent Causal Content for Multi-Source Domain Adaptation

Multi-source domain adaptation (MSDA) learns to predict the labels in target domain data, under the setting that data from multiple source domains are labelled and data from the target domain are unlabelled. Most methods for this task focus on learning invariant representations across domains. However, their success relies heavily on the assumption that the label distribution remains consistent across domains, which may not hold in general real-world problems. In this paper, we propose a new and more flexible assumption, termed \textit{latent covariate shift}, where a latent content variable $\mathbf{z}_c$ and a latent style variable $\mathbf{z}_s$ are introduced in the generative process, with the marginal distribution of $\mathbf{z}_c$ changing across domains and the conditional distribution of the label given $\mathbf{z}_c$ remaining invariant across domains. We show that although (completely) identifying the proposed latent causal model is challenging, the latent content variable can be identified up to scaling by using its dependence with labels from source domains, together with the identifiability conditions of nonlinear ICA. This motivates us to propose a novel method for MSDA, which learns the invariant label distribution conditional on the latent content variable, instead of learning invariant representations. Empirical evaluation on simulation and real data demonstrates the effectiveness of the proposed method

Identifiable Latent Polynomial Causal Models Through the Lens of Change

Causal representation learning aims to unveil latent high-level causal representations from observed low-level data. One of its primary tasks is to provide reliable assurance of identifying these latent causal models, known as identifiability. A recent breakthrough explores identifiability by leveraging the change of causal influences among latent causal variables across multiple environments \citep{liu2022identifying}. However, this progress rests on the assumption that the causal relationships among latent causal variables adhere strictly to linear Gaussian models. In this paper, we extend the scope of latent causal models to involve nonlinear causal relationships, represented by polynomial models, and general noise distributions conforming to the exponential family. Additionally, we investigate the necessity of imposing changes on all causal parameters and present partial identifiability results when part of them remains unchanged. Further, we propose a novel empirical estimation method, grounded in our theoretical finding, that enables learning consistent latent causal representations. Our experimental results, obtained from both synthetic and real-world data, validate our theoretical contributions concerning identifiability and consistency

MiR-124-3p negatively impacts embryo implantation via suppressing uterine receptivity formation and embryo development

Abstract During embryo implantation, blastocyst interacts with the receptivity endometrium and the endometrial epithelium secretes nurturing fluid to support embryonic development. Interferon-λ (IFN-λ) is a novel, non-redundant regulator that participates in the fetal–maternal interaction; however, the precise molecular mechanism underlying its impact on uterine receptivity remains elusive. Here, microarray profiling revealed that 149 specific miRNAs were differentially expressed in the human endometrial cells following IFN-λ treatment. In particular, miR-124-3p expression was significantly reduced after IFN-λ treatment (p < 0.05). An in vivo mouse pregnancy model showed that miR-124-3p overexpression notably decreased embryo implantation rate and led to an aberrant epithelial phenotype. Furthermore, miR-124-3p negatively impacted the migration and proliferation of endometrial cells, and hindered embryonic developmental competence in terms of blastocyst formation and global DNA re-methylation. Downstream analysis showed that LIF, MUC1 and BCL2 are potential target genes for miR-124-3p, which was confirmed using western blotting and immunofluorescence assays. In conclusion, IFN-λ-driven downregulation of miR-124-3p during embryo implantation modulates uterine receptivity. The dual functional role of miR-124-3p suggests a cross-talk model wherein, maternal endometrial miRNA acts as a transcriptomic modifier of the peri-implantation endometrium and embryo development

Sperm-borne microRNA-34c regulates maternal mRNA degradation and preimplantation embryonic development in mice

Abstract Background Studies have shown that sperm-borne microRNAs (miRNAs) are involved in mammalian preimplantation embryonic development. In humans, spermatozoan miR-34c levels are correlated with in vitro fertilization outcomes, such as embryo quality and the clinical pregnancy and live birth rates. In rabbits and cows, miR-34c improves the developmental competence of embryos generated by somatic cell nuclear transfer. However, the mechanisms underlying the regulation of embryonic development by miR-34c remain unknown. Methods Female C57BL/6 mice (6–8 weeks old) were superovulated, and pronucleated zygotes were collected and microinjected with an miR-34c inhibitor or a negative-control RNA. The embryonic development of the microinjected zygotes was evaluated, and the messenger RNA (mRNA) expression profiles of the embryos at the two-cell, four-cell and blastocyst stages (five embryos per group) were determined by RNA sequencing analysis. Gene expression levels were verified by reverse transcription–quantitative polymerase chain reaction. Cluster analysis and heat map visualization were performed to detect differentially expressed mRNAs. Pathway and process enrichment analyses were performed using ontology resources. Differentially expressed mRNAs were systematically analyzed using the Search Tool for the Retrieval of Interacting Genes/Proteins database to determine their biological functions. Results Embryonic developmental potential was significantly reduced in zygotes microinjected with the miR-34c inhibitor compared with those microinjected with a negative-control RNA. Two-cell stage embryos microinjected with an miR-34c inhibitor presented altered transcriptomic profiles, with upregulated expression of maternal miR-34c target mRNAs and classical maternal mRNAs. Differentially expressed transcripts were mainly of genes associated with lipid metabolism and cellular membrane function at the two-cell stage, with cell-cycle phase transition and energy metabolism at the four-cell stage; and with vesicle organization, lipid biosynthetic process and endomembrane system organization at the blastocyst stage. We also showed that genes related to preimplantation embryonic development, including Alkbh4, Sp1, Mapk14, Sin3a, Sdc1 and Laptm4b, were significantly downregulated after microinjection of an miR-34c inhibitor. Conclusions Sperm-borne miR-34c may regulate preimplantation embryonic development by affecting multiple biological processes, such as maternal mRNA degradation, cellular metabolism, cell proliferation and blastocyst implantation. Our data demonstrate the importance of sperm-derived miRNAs in the development of preimplantation embryos

Mass Capture repository of scanned images

Consists of scanned and enhanced images from microfilm reels held at Library Archives Canada. Organized in file folders labelled by reel number, these images are of CI 9 documents, state documents issued under the Chinese Immigration Act of 1885. Issued from 1885 to 1953, CI 9 documents include date of birth, place of residence, occupation, identifying marks, known associates, and, significantly, identification photographs. The CI 9 documents were microfilmed in 1963 and the originals destroyed. As part of a SSHRC-funded research project led by Dr. Lily Cho, this data set consists of over xxx reconstituted digital reproductions of CI 9 documents.Dataset of reconstituted digital reproductions of CI 9 documents, issued under the Chinese Immigration Act of 1885, from microfilm reels held by Library Archives Canada.Mass Capture is supported in part by funding from the Social Sciences and Humanities Research Council, grant number 435-2016-0948

Cytokinin-Induced Parthenocarpic Fruit Development in Tomato Is Partly Dependent on Enhanced Gibberellin and Auxin Biosynthesis

<div><p>Fruit set of plants largely depends on the biosynthesis and crosstalk of phytohormones. To date the role of cytokinins (CKs) in the fruit development is less understood. Here, we showed that parthenocarpic fruit could be induced by 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU, an active CK) in tomato (<i>Solanum</i><i>lycopersicum</i> cv. Micro-Tom). The fresh weight of CPPU-induced parthenocarpic fruits was comparable with that induced by GA₃. Importantly, CPPU-induced parthenocarpy was found to be compromised by simultaneous application of paclobutrazol (a GA biosynthesis inhibitor), and this effect could be restored by exogenous GA₃. Like pollination, CPPU-induced fruit showed enhanced accumulation of GA₁₊₃ and indole-3-acetic (IAA), which were accompanied by elevated expression of GA biosynthesis genes like <i>SlGPS, SlGA20ox1, SlGA20ox2</i> and <i>SlGA3ox1</i>, and IAA biosynthesis gene <i>ToFZY</i>. Elevated GAs level in CPPU-induced fruits was also associated with down-regulation of GA inactivation genes, namely <i>SlGA2ox1,2,3,4,5</i> in comparison with untreated control. These results suggested that CKs may induce parthenocarpy in tomato partially through modulation of GA and IAA metabolisms.</p> </div

Dosage- and site-dependent retention of black carbon and polycyclic aromatic hydrocarbons in farmland soils via long-term biochar addition

Abstract Biochar, a soil conditioner containing significant amounts of polycyclic aromatic hydrocarbons (PAHs), has gained widespread popularity in agricultural practices due to its advantages in improving soil fertility and carbon sequestration. While biochar may increase soil black carbon (BC) and PAH contents, the quantitative accumulation of BC and PAHs in different soil environments under varying biochar addition dosages remains poorly understood. Here, we investigated the content and composition of black carbon (evaluated using benzene polycarboxylic acids, BPCAs) and PAHs in soils treated with different biochar addition dosages from two long-term experimental farmlands in Ningxia (5-year) and Shandong (7- and 11-year), China. Results showed that increasing cumulative biochar dosage caused elevated contents of black carbon and PAHs, accompanied by decreases in their retention efficiencies. Contrasting retention was observed between sites, with the Shandong site characterized by higher retention efficiencies of BPCAs and lower retention efficiencies of PAHs, possibly owing to its higher temperature, more sandy soil texture, less irrigation, and lower sunlight intensity. Despite both black carbon and PAHs originating from biochar and sharing similar condensed aromatic structures, there was no significant correlation between the contents of black carbon and PAHs, indicating distinct behaviors and fates of these compounds. These findings emphasize the importance of optimizing biochar addition dosages and considering site-specific environmental factors for effective soil black carbon sequestration through biochar application. Graphical Abstrac

Response of unpollinated tomato ovaries to CPPU and GA₃ treatment (10 µl/ovary; Concentration of CPPU 100 mg L^-1 and GA₃ 200 mg L^-1).

<p>(A) Response of fruit FW to GA₃, CPPU or GA₃ plus CPPU. (B) Response of fruit pericarp thickness to GA₃, CPPU or GA₃ plus CPPU. (C) Transverse sections of fruit treated with GA₃, CPPU or GA₃ plus CPPU. CPPU and ZT were applied at anthesis. (D) Microscopic analysis of the pericarp in 20 DAA fruits. UP, unpollinated; P, pollinated. Fruits were collected 20 days after CPPU and/or GA₃ application. Values are means of three replicates with 10 ovaries as a replicate (±SD). Significant differences (P<0.05) between treatments are indicated by different letters according to Tukey’s test.</p

Changes in the concentration of active GA (GA₁₊₃) (ng g^-1 FW) in the CPPU-induced and pollinated fruits.

<p>All the ovaries and fruits were collected at 5, 10, 20 DAA, and applied with CPPU (10 µl/ovary, concentration of CPPU 100 mg L^-1). UP, unpollinated; P, pollinated. All experiments were performed with three biological replicates and two technical replicates. Significant differences (P<0.05) between treatments are indicated by different letters according to Tukey’s test.</p